Testing for cervical cancer among women in England has fallen to a 10-year low, a cancer charity said.
Despite cervical screening saving 5,000 lives every year in the UK, 20% of women are not being tested.
The charity said many feel the screening is not necessary or relevant to them, while others are unaware of the causes, symptoms and ways to prevent the cancer.
Some women miss or delay tests because of work commitments, while others book time off work because they are too embarrassed to discuss it with their bosses.
Jo’s Cervical Cancer Trust - the UK’s only dedicated cervical cancer charity - is urging more women to attend screenings.
Robert Music, the trust’s director, said: “Every day eight women are diagnosed with cervical cancer and three lives are lost to the disease. Cervical screening can help reduce these numbers.
“The screening programme saves 5,000 lives each year in the UK yet 20% of women are not attending their cervical screening test. The more we can do to stress the importance of this life-saving test the better.
“With such a worrying decline in numbers our campaign is also targeting key cities where uptake is below the national average.
“Adverts urging eligible women to get screened will adorn buses across London, Birmingham, Cardiff, Glasgow and Manchester, reaching a potential 5.5 million people.”
Over the last decade the number of women being tested for the cancer has fallen, despite a dramatic rise in 2009 following the death of Big Brother star Jade Goody from the disease.
The “Jade Goody effect” saw more than 400,000 women in England tested for cervical cancer between mid-2008 and mid-2009.
It said a poll, carried out by YouGov, showed that since then numbers have declined.
Now fewer than 80% of women take up the screening - more than one in five women between the ages of 25 and 64 and one in three under 35 are not being tested.